BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Memento EPFL// BEGIN:VEVENT SUMMARY:The Physics and Applications of high Q optical microcavities: Cavi ty Quantum Optomechanic DTSTART:20160701T151500 DTSTAMP:20260506T173156Z UID:f1f562f22063ac0ca160497ffe5dc8ab01ba51c8e0ecf500e7f89b62 CATEGORIES:Conferences - Seminars DESCRIPTION:Tobias J. Kippenberg (PhD\, Dr. habil.)\nEPFF\, Switzerland\nL aboratory of Photonics and Quantum Measurements\nThe mutual coupling of op tical and mechanical degrees of freedom via radiation pressure has been a subject of interest in the context of quantum limited displacements measur ements for Gravity Wave detection for many decades (1\,2).  The pioneerin g work of Braginsky predicted that radiation pressure can give rise to dyn amical backaction\, which allows cooling and amplification of the internal mechanical modes of a mirror coupled to an optical cavity and moreover es tablishes a fundamental measurement limit via radiation pressure quantum f luctuations. Experimentally these phenomena remained however inaccessible many decades due to the faint nature of the radiation pressure force.  A decade ago\, it was discovered that optical microresonators with ultra hig h Q\, not only possess ultra high Q optical modes\, but moreover mechanica l modes that are mutually coupled via radiation pressure (3). The high Q o f the microresonators\, not only enhances nonlinear phenomena – which en ables for instance optical frequency comb generation (4\,5) as well as tem poral soliton formation (6\,7) – but also enhances the radiation pressur e interaction. This has allowed the observation of radiation pressure phen omena in an experimental setting and is an underlying principle of the res earch field of cavity quantum optomechanics (8\,9). In this talk\, I will describe a range of optomechanical phenomena that we observed using high Q optical microresonators. Radiation pressure back-action of photons is sho wn to lead to effective cooling (1\,2\,10\,11) of the mechanical oscillato r mode using dynamical backaction. Sideband resolved cooling\, combined wi th cryogenic precooling enables cooling the oscillators such that it resid es in the quantum ground state more than 1/3 of its time (12). Increasing the mutual coupling further\, it is possible to observe quantum coherent c oupling (12) in which the mechanical and optical mode hybridize and the co upling rate exceeds the mechanical and optical decoherence rate (7). This regime enables a range of quantum optical experiments\, including state tr ansfer from light to mechanics using the phenomenon of optomechanically in duced transparency (13). Moreover\, the optomechanical coupling can be exp loited for  measuring the position of a nanomechanical oscillator in the timescale of its thermal decoherence (14)\, a basic requirement for prepar ing its ground-state using feedback as well as (Markovian) quantum feedbac k. This regime moreover enables to explore quantum effects due to the radi ation pressure interaction\, notably quantum correlations in the light fie ld that give rise to optical squeezing or sideband asymmetry (15).\nThe op tomechanical toolbox developed in the past decades enables to extend quant um control\, first developed for atoms\, and recently for superconducting quantum circuits\, to be extended to solid state mechanical oscillators. N ew frontiers that are now possible include for example the generation of n on-classical states of motion via post-selection (16)\, mechanical quantum squeezing\, or interfaces from radio-frequency to the optical domain (17) . Time\, permitting\, recent experiments that probe cavity optomechanics r eserved dissipation regime in a microwave opto-mechanical system will be d iscussed\, which provide a means to realize a cold dissipative reservoir f or microwave light (18) a building block for non-reciprocal devices (19). LOCATION:CE 1 5 https://plan.epfl.ch/?room==CE%201%205 STATUS:CONFIRMED END:VEVENT END:VCALENDAR